Recently, many investigations have been made of electrode systems, as electrode catalysts, which have undergone surface modification with a macrocyclic compound, such as porphyrin, chlorophyll, phthalocyanine, tetraazaannulene or Schiff base, or a derivative thereof. And these electrode systems are expected to be applied, as electrode catalysts which take the place of platinum (Pt) and its alloys, to the cathode of (oxygen-hydrogen) fuel cells, such as phosphoric acid fuel cells or polymer electrolyte fuel cells, by utilizing the electrochemical multielectron reduction properties of molecular oxygen (O2) (see Hyomen Gijyutsu (The Journal of the Surface Finishing Society of Japan)”, vol. 46, No. 4, pp. 19-26 and “POLYMERS FOR ADVANCED TECHNOLOGYS”, No. 12, pp. 266-270, 2001).
However, the catalytic activity of the electrode systems utilizing any of the above macrocyclic compounds is insufficient to use the systems in fuel cells. Under these circumstances, there have been demands for development of catalyst materials having higher catalytic performance and serviceability.